The heart functions as a muscular pump, continuously circulating blood throughout the body to deliver oxygen and nutrients. Its effective pumping is fundamental for sustaining life and overall health. When the heart’s pumping action becomes less efficient, it can impact the body’s ability to receive adequate blood flow. This can lead to a range of symptoms, indicating that the heart is struggling to meet the body’s demands for blood circulation.
Understanding Ejection Fraction
Ejection fraction (EF) measures the percentage of blood pumped out of the left ventricle, the heart’s main pumping chamber, with each contraction. It represents how effectively the heart squeezes blood into the aorta and to the rest of the body. This metric is commonly assessed using imaging tests, with an echocardiogram being the most frequently used method, employing sound waves to create images of the beating heart.
A normal left ventricular ejection fraction (LVEF) is 50% to 70%. A mildly reduced LVEF is 41% to 49%, and an LVEF of 40% or less is categorized as reduced. This measurement helps healthcare professionals gauge the heart’s pumping strength.
Heart Failure with Preserved Ejection Fraction
Heart Failure with Preserved Ejection Fraction (HFpEF) is a condition where the heart’s ejection fraction appears normal, usually 50% or higher. Despite this, individuals experience heart failure symptoms because the heart muscle has become stiff and less able to relax properly between beats. This stiffness prevents the left ventricle from filling adequately with blood, leading to insufficient overall volume pumped out to meet the body’s needs.
Common causes of HFpEF include chronic conditions such as high blood pressure, diabetes, and obesity. Coronary artery disease, atrial fibrillation, and chronic kidney disease are also associated risk factors. Patients often experience symptoms like shortness of breath, particularly with activity or when lying down, fatigue, and swelling in the legs, ankles, and feet, which result from fluid accumulation due to the heart’s inadequate filling.
Heart Failure with Reduced Ejection Fraction
Heart Failure with Reduced Ejection Fraction (HFrEF), also known as systolic heart failure, occurs when the left ventricle is weakened and cannot pump enough blood out to the body. The heart muscle’s ability to contract forcefully is impaired, leading to a lower ejection fraction, typically 40% or less. This results in insufficient blood flow to the body’s organs and tissues.
Various cardiovascular conditions can lead to HFrEF. Common causes include coronary artery disease, where narrowed arteries limit blood flow to the heart muscle, and a history of heart attack, which can damage and weaken the heart muscle. Other factors include high blood pressure, certain arrhythmias, heart valve disease, and myocarditis, an inflammation of the heart muscle. Symptoms are often similar to HFpEF, such as shortness of breath, fatigue, and swelling, reflecting the heart’s diminished pumping strength and subsequent fluid buildup.
Why the Distinction Matters for Treatment
Distinguishing between Heart Failure with Preserved Ejection Fraction (HFpEF) and Heart Failure with Reduced Ejection Fraction (HFrEF) is important because their underlying mechanisms differ significantly, guiding distinct treatment approaches. While both can present with similar symptoms like shortness of breath and fatigue, the heart’s specific dysfunction dictates how medical interventions are applied. For HFrEF, where the heart muscle is weakened and struggles to pump blood effectively, treatments often focus on improving the heart’s contractile function.
Guideline-directed medical therapies for HFrEF include medications such as ACE inhibitors, beta-blockers, mineralocorticoid receptor antagonists, and SGLT2 inhibitors, which work to improve heart function and reduce the risk of hospitalization and mortality. These medications aim to relax blood vessels, reduce stress on the heart, and help the heart pump more efficiently. In contrast, treatment strategies for HFpEF focus on managing the underlying conditions that contribute to the heart’s stiffness and impaired filling.
Treatments for HFpEF involve controlling blood pressure, managing diabetes, and addressing obesity, as these conditions can stiffen the heart over time. Diuretics are used to relieve fluid overload and symptoms like swelling and shortness of breath. While specific medications like SGLT2 inhibitors have shown promise in reducing cardiovascular events and hospitalizations for HFpEF, the overall approach focuses on addressing comorbidities and improving the heart’s relaxation and filling abilities rather than directly enhancing pumping strength. This tailored approach underscores why accurate diagnosis of the ejection fraction type is important for effective patient care.